Chainstub

What

An API for nonprofits that accept stablecoins directly: it watches the charity's wallet, matches each inbound RLUSD or USDC transfer to a donor, issues the IRC 170 acknowledgment automatically, and publishes a ledger view tying the on-chain receipt to the program expenditure it funded. Donors get evidence the dollar arrived; auditors and state regulators get records in the form they already accept.

Grounded in (2025-2026 signals)

The Giving Block's 2026 report counts over $100 million of crypto donations in 2025, more than $32 million in stablecoins, with RLUSD at 17% and USDC at 11% of volume, 'a rail with no card fees and a receipt on a public ledger, under a federal statute since the GENIUS Act of July 18, 2025.' YC's Fall 2026 RFS includes The Best Time to Build in Crypto.

What it rides

Stablecoin donations reached $32 million: the rail now exists under a federal statute, but the substantiation and evidence layer that makes an on-chain gift legible to the IRS, a donor and a charity auditor does not.

Why now

Stablecoin giving tripled into a $32 million category in 2025, the first full year after the GENIUS Act of July 18, 2025 gave the rail a federal statute, and every one of those gifts still needs a written acknowledgment the blockchain does not produce; the cost removed is the card processing fee, replaced by a flat per-receipt price.

Wedge: first customer and entry point

Twenty crypto-forward nonprofits that already hold their own wallets rather than selling through an intermediary; ship wallet-watching, donor matching and auto-acknowledgment first, the spend-side ledger second.

Closest real companies, as the generator saw them

The Giving Block processes crypto donations as an intermediary platform; Chainstub sells the receipt and evidence layer to charities that take stablecoins directly into their own wallets, and can sit alongside any processor.

Main risk

Stablecoin giving stays concentrated inside The Giving Block's platform, leaving too few direct-wallet charities to sell to.

Nothing in the directory matches this concept's terms.

No matching grants or programs tracked; 2 startup-relevant grants exist in Fintech overall.

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